On the Use of PAH Molecular Diagnostic Ratios in Sewage Sludge for the Understanding of the PAH Sources - Is This Use Appropriate?

In many studies, the sources of polycyclic aromatic hydrocarbons (PAHs) in various environmental samples have been qualitatively determined by the various molecular diagnostic ratios. For example, a widely used concentration ratio is the anthracene (Ant)/[Ant + phenanthrene (Phe)], and if this is lower than 0.10, it is taken as indicative of non burnt fossil fuel, whereas if this ratio exceeds 0.10, this suggests combustion sources. Similarly, many other ratios exist (Table 1), and are used to reveal petrogenic or pyrogenic origin, fuel or wood combustion, or traffic related sources (Brandli et al., 2007; Cai et al., 2007). When these ratios are used to determine the sources, it is hypothesized that paired chemicals are diluted to a similar extent and that the ratios remain constant en route from sources to receptors, although in many cases it has been proven that this does not happen (Zhang et al., 2005). Recently, Dai et al. (2007; but also in the past, i.e Blanchard et al., 2004), used these ratios for the characterization of sources of PAHs ending in the sewage sludge. The authors of the present correspondence claim that such use is not appropriate based on two main reasons: 1) The mixing and homogenization that takes place during the transportation of wastewaters; 2) The treatment that the wastewaters undergo at the various treatment steps. These two parameters will be discussed to prove the afore-mentioned statement about the improper use of PAH molecular diagnostic ratios in sewage sludges.

KATSOGIANNIS Athanasios;  TERZI Eleni;  CAI Quan-Ying; 

2007-10-02

PERGAMON-ELSEVIER SCIENCE LTD

JRC37582

0045-6535,   

http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V74-4P6TGYS-2&_user=4900406&_coverDate=10%2F31%2F2007&_alid=626120685&_rdoc=1&_fmt=summary&_orig=search&_cdi=5832&_sort=d&_docanchor=&view=c&_ct=25&_acct=C000036252&_version=1&_urlVersion=0&_useri,    https://publications.jrc.ec.europa.eu/repository/handle/JRC37582,   

10.1016/j.chemosphere.2007.05.084,